Pipe apparatus



Oct. 14, 1969 FOWLER 3,472,530

PIPE APPARATUS Filed Sept. 20, 1966 2 Sheets-Sheet 1 dip/N7 M Few/er 1mENTOR.

Oct. 14, 1969 J FOWLER 3,472,530

PIPE APPARATUS Filed Sept. 20, 1966 2 Sheet=:Sheef 2 "Jmn/x/ ow/w W [NEN TOR.

United States Patent Int. Cl. F161 3/02 US. Cl. 285-3 Claims ABSTRACT OFTHE DISCLOSURE Pipe suspension apparatus for supporting casing or thelike in a well comprising a wellhead, a tubular mandrel concentricallydisposed in the wellhead and suspension means mounted on the mandrel.The wellhead is provided with internal annular grooves, the upper andlower limits of which are frusto-conical surfaces. The suspension meanscomprises a plurality of segments whose outer faces conform to the shapeof the wellhead grooves. In one embodiment the tubular mandrel hasseveral downwardly facing shoulders formed by uniformly reducedcylindrical exterior portions. The segments are resiliently mounted onthe mandrel and held near its lower portions by the wellhead sidewalland at least one of the downwardly facing shoulders. As the mandrel islowered into the wellhead these segments move radially outward to engagethe wellhead grooves freeing them to move upwardly relative to themandrel until a larger diameter portion moves between the segmentslocking them in the extended position supporting the mandrel within thewellhead. A hold down latch is mounted on the mandrel to laterallyengage the lower edge of the segments to also prevent upward movement ofthe mandrel. In another embodiment the mandrel is tapered and thesegments have corresponding tapered inner faces. The lowermost wellheadgroove projects slightly into the wellhead bore providing a stop for thesegments on downward movement of the mandrel and suspension means. Onfurther downward movement of the mandrel the tapered surfaces of themandrel and segments and frusto-conical surfaces of the wellhead groovecooperate to force the segments radially outward and upwardly withrespect to both mandrel and wellhead, into the grooves locking themandrel against downward movement in the wellhead.

This invention pertains to oil and gas well apparatus and moreparticularly to apparatus used to hang casing or tubing within the well.

Normally in well pipe suspension apparatus, a pipe hanger, to whichcasing or tubing is attached for suspension, is supported by supportmeans within a wellhead or casing. The support means usually is in theform of an internal shoulder or tapered portion of the well head. Thisresults in reduced access to the well bore. Thus, the passage of wellquipment during drilling and completion of the well is limited todiameters somewhat less than the wellhead bore. This may be overcome onsurface wells by use of retractable support means. But, in relativelyinaccessible wellheads, such as those in underwater wells, this may bevery costly and diflicult.

To provide for a full internal diameter relatively free fromobstructions, it is, therefore, necessary to provide a support meanswhich does not substantially violate the internal diameter of thewellhead bore. In an underwater well it is also necessary that thehanger device be capable of engaging the support means while beinglowered from a remote location.

A principal object of the present invention is to provide a means ofhanging casing or tubing so that very little or no shoulder is requiredon the supporting element, providing substantially full opening accessto the well.

Another object of the invention is to provide a pipehanging supportwhich allows relatively complete access to the well bore and pipehangers which may easily be installed in remotely located wellheads suchas those underwater.

Other objects will become apparent on further description of theinvention.

Briefly stated, the invention utilizes hanger equipment comprising amandrel, to which pipe is attached for suspension, and suspension meansmounted thereon. The suspension means is held in a neutral positionuntil automatically released by engagement with preformed grooves on theinternal wall of a wellhead or support element. On being released, thesuspension means anchors the suspended pipe to the support element,without the necessity of substantial internal shoulders.

In the present invention annular internal grooves are provided in awellhead leaving a substantially open bore therethrough. In oneembodiment the lower limit surface of one groove projects slightly intothe bore. A tubular mandrel is provided on which a suspension means ismounted comprising segments whose outer faces conform to the shape ofthe wellhead grooves. In one embodiment these segments are resilientlymounted on a lower reduced diameter of the mandrel so that when themandrel is lowered into the wellhead these segments move radiallyoutward engaging the wellhead grooves and freeing the mandrel forfurther downward movement to a position between the segments wherebythey are locked outwardly by a larger diameter portion of the mandrel.The mandrel and attached casing are then supported in the wellhead bythe segments. A hold down means is also provided to then prevent themandrel from moving upwardly in the wellhead. In another embodiment foruse with the slightly projecting lower groove surface the mandrel istapered and the inner faces of the segments are tapered to cooperatetherewith. The segments are initially mounted on the lower part of themandrel within a diameter slightly less than the well bore. As themandrel is lowered into the wellhead the lower edge of the segmentscontact the projecting lower groove and are forced outwardly into thegrooves by the cooperating tapered mandrel and segment faces to supportthe mandrel and attached apparatus.

Several embodiments of the invention are described herein. For a betterunderstanding of the invention and its embodiments reference is now madeto the following description and the accompanying drawings, wherein:

FIGURE 1 is an elevation in partial section of one embodiment of theinvention shown in a partially engaged position;

FIGURE 2 is an elevation in partial section of another embodiment of theinvention showing initial engagement of the suspension means with thewellhead;

FIGURE 3 is an elevation in partial section of the embodiment of FIGURE1 adapted for surface installation.

Referring first to FIGURE 1, the first embodiment of the invention willbe described. A pipe hanger 10 is shown supporting casing 11 withinwellhead 1.2. Attached to the upper end of hanger is riser 13, which inunderwater casing operations may constitute a casing extension reachingto the surface of the water.

Hanger 10 includes a tubular mandrel 14 which has connection means ateach end thereof to receive casing 11 and riser 13. Near the base ofmandrel 14 a groove 15 is machined to form a lower reaining shoulder 16for cooperation with a portion of segments to be explained later. Movingupwardly from groove 15, mandrel 14 has stepped up diameters so thatupper retaining shoulder 17 and support shoulder 18 are provided, thefunction of which will be explained later. The vertical distancesbetween lower retaining shoulder 16 and upper retaining shoulder 17 andbetween upper retaining shoulder 17 and support shoulder 18 aresubstantially the same.

Suspension means is provided including segments 20 conveniently formedby machining an annular ring and cutting it into four segments 20. Theouter faces of segments 20 are formed to cooperate with preformedgrooves 21 on the interior circumference of wellhead 12. The inner facesof segments 20 are correlatively conformed to the shape of groove 15 andthe lower diameter of mandrel 14 so that on compression of a spring 22segment 20 will be prevented from upward movement by lower retainingshoulder 16 and upper retaining shoulder 17. On outward movement ofsegments 20, retaining shoulders 16 and 17 are cleared allowing segments20 to move upwardly on mandrel 14 until stopped by support shoulder 18and upper retaining shoulder 17.

A light metal cage holds and guides segments 20 so all segments areassured of moving up or down in unison. The cage is formed by joiningupper ring 29a and lower ring 29b with vertical strips 29c betweensegments 21). Small lugs 20a and 20b are provided on the upper and lowerportion of segments 20 which ride in slots a and 30b. Thus, segments 20are prevented from being forced free from hanger 10.

Each of the four segments 20 may occupy an arc substantially less than90 degrees, for example, 45 degrees, so that space is maintained betweensegments 20 to allow annular fluid flow past hanger 10. Shoulder 13 mayalso be provided with passages 18a to aid in fluid flow. However, ducts(shown by hidden lines) may be provided in wellhead 12, making thisunnecessary.

Hold down latch 23 mounted in a groove 24 on lower diameter 19 is springbiased to extend out of groove 24. The latch has an upwardly andoutwardly beveled face so that a flat shoulder 25 is provided. Latchretractor 26 is inserted through a vertical hole in mandrel 14communicating with groove 24. It has a conical tip 27 to cooperate witha conical depression 28 in hold down latch 23. In its spring biasedposition (as shown), latch 23 is extended so that the point of conicaltip 27 rests on the inner edge of depression 28. If latch retractor 26is forced downwardly by a tool adapted for such purpose, latch 23 willbe completely retracted in groove 24 due to the cooperation of conicaltip 27 and depression 28.

In operation hanger 10 would be lowered into wellhead 12 with casing 11and riser 13 attached thereto. Segments 20 would be depressed againstmandrel 14 and held in a neutral position by upper and lower retainingshoulders 16 and 17 and the interior wall of wellhead 12. As hanger 10moves downwardly, segments 20 become juxtapoisitioned to grooves 21.Spring 22 causes segments 20 to be forced into cooperative grooves 21 onwellhead 12. This frees mandrel 14 for further movement downwardrelative to segments 20 and grooves 21. As mandrel 14 continuesdownward, it comes to a stop; support shoulder 18 and upper retainingshoulder 17 resting on ring 29a and segment shoulder 200 respectively.Hold down latch 23, due to its beveled face, has been retracted allowingsegments 20 to pass upwardly. With segments 20 in their uppermostposition, hold down latch 23 is free to spring outwardly. Thus, segments20 are locked outwardly by mandrel 14; hanger 10 and casing 11 are helddown by hold down latch 23.

To remove hanger 10 and casing 11, latch retractor 26 is forced down, asby dropping an annular ring onto it, so that conical tip 27 cooperatingwith depression 28 causes hold down latch 23 to be retracted. Mandrel 14and casing 11 are then pulled upward. Segments 20 are forced againstmandrel 14 due to the cooperating beveled surfaces of grooves 21 andsegments 20. Hanger 10 is thereby freed, allowing its removal along withattached casing 11.

Another embodiment of the invention is described with reference toFIGURE 2. Hanger 66 is shown supporting casing 61 within wellhead 62.Attached to the upper end of hanger 60 is riser 63.

Hanger 60 includes a tubular mandrel 64 with connection means, such asthreads, at each end thereof to receive casing 61 and riser 63. Theexterior of mandrel 64 is tapered in a downwardly converging surface.Shoulders 65 and 66 are provided at the upper and lower ends of thetapered surface. Passageways 71 in shoulders 65 and 66 allow passage offluid by hanger 60.

Suspension means are attached to mandrel 64 includin segments 67.Segments 67 are formed by machining grooves on the exterior of acylinder, tapering the interior of the cylinder to cooperate with thetapered surface of mandrel 64, and cutting into vertical segments. As inanother embodiment described herein, space may be left between segments67 to allow fluid passage, but if desired ducts may be provided throughthe sidewall of wellhead 62. Segments 67 rest on shoulder 66 and areheld against the tapered portion of mandrel 64 by guide rods 68 whichpass through holes in segments 67 parallel to cooperating taperedsurfaces of mandrel 64 and segments 67. Guide rods 68 are attached toshoulder 66 by screw threads. Shear screw 79 passes through segments 67into mandrel 64 holding segments 67 at their lowermost position onmandrel 64. Shoulder 65 may be in the form of a ring threadinglyconnected to mandrel 64. This will allow segments 67 to be easilymounted on guide rods 68 by removing the ring and sliding segments 67over rod 68.

The interior of wellhead 62 has grooves 69 machined on it to cooperatewith the outer face of segments 67 to form a key lock. The bottomsurface of the last groove in wellhead 62 extends slightly into the boreof wellhead 62 forming a very small shoulder at 70. Shoulder 70 is onlywide enough to cause shearing of screw 79 by interference with the loweredge of segment 67, and is not wide enough to provide enough support tosupport the hanger and the casing.

In operation, hanger 60 and casing 61 would be lowered into wellhead 62.The lower edge of segments 67 would contact shoulder 70 causing screw 79to be sheared on further downward movement. This would free segments 67to move upward and radially outward relative to mandrel 64. On furtherdownward movement of mandrel 64, segments 67 would be forced intogrooves 69 by the cooperating tapered surfaces on mandrel 64 andsegments 67, finally coming to a stop on contacting shoulder 65. Thus,an effective key lock suspension is obtained, anchoring hanger 60 andcasing 61 to wellhead 62.

To remove hanger 60 and attached casing 61, an upward force is appliedto them. Segments 67 are forced inwardly due to the cooperating beveledsurfaces of grooves 69 and segments 67 and guide rod 68. Thus, hailnlger60 and casing 61 are free to be removed from the we Although, theembodiments described heretofore are for underwater extended casingoperation, the invention may be readily adapted for surfaceinstallation. In such use, an annular seal could be provided. Forexample, seal as shown in FIGURE 3 could be used at the upper end ofeither of hangers 10 or 60 (FIGURES 1 and 2). A shoulder 91 is providedon mandrel 93. An annular seal 90 is mounted between shoulder 91 and theupper end of 92 suspension means. Resilient ring 94, mounted betweenholding rings 95 and 96, would be compressed as mandrel 93 movesdownwardly forcing seal 90 against edge of suspension means 92,effectively sealing on both sides thereof.

As can be seen in the embodiments of the invention described herein,effective pipe suspension is obtained without substantial internalshoulders on the supporting wellhead. Installation and removal are botheasily and remotely obtained.

I claim:

1. Pipe suspension apparatus comprising:

wellhead means having annular grooves therein, said grooves each beingdefined by a bottom Wall and two side walls;

tubular mandrel means concentrically disposed in said wellhead means,said mandrel means having a plurality of downwardly facing shouldersformed by correspondingly reduced outside diameters of said mandrelmeans;

suspension means releasably attached to said mandrel means comprisingsegments resiliently mounted and longitudinally held to said mandrelmeans by the side wall of said wellhead means and at least one of saiddownwardly facing shoulders on said mandrel means, said suspensionmeans, wellhead means and mandrel means all being so constructed andarranged so that said segments will engage said side walls of saidgrooves on said wellhead means as said mandrel is lowered into saidwellhead means and allow said mandrel means to move axially downwardrelative to said segments, said mandrel means stopped only by contact ofsaid segments with another of said downwardly facing shoulders on saidmandrel means thereby suspending said tubular mandrel means within saidwellhead means.

2. The combination of claim 1; and hold down means resiliently mountedon said mandrel means engageable with at least one of said segments insaid stopped position to hold said suspension means in locked positionwith said wellhead means, said hold down means being retractable torelease said suspension means for disengagement.

3. Pipe suspension apparatus comprising:

wellhead means having preformed annular grooves therein; the lowerlimits of said grooves being defined by downwardly and inwardlyconverging frustoconical surfaces, the lower limit surface of thelowermost of said annular grooves extending slightly into the bore ofsaid wellhead means;

tubular mandrel means concentrically disposed in said wellhead means,the exterior of which is provided with a downwardly converging taperedsurface; suspension means mounted on said mandrel means, said suspensionmeans including segment means having outer faces correlatively formed toengage said preformed grooves and inner faces tapered to cooperate withsaid mandrel means tapered surface, said suspension means, wellheadmeans and mandrel means being so constructed and arranged so that assaid tubular mandrel means is lowered into said wellhead the lower edgeof said segment means first contacts said extending lowermost groovesurface causing said segment means to be forced upwardly and outwardlyrelative to both said mandrel means and said wellhead means into saidpreformed grooves thereby supporting said mandrel means within saidwellhead.

4. The combination of claim 3 wherein the upper limits of each of saidgrooves is defined by upwardly and inwardly converging frusto-conicalsurfaces substantially in contact with said segment means in saidsupporting position so that on upward movement of said mandrel meanssaid segment means are forced radially inward along said upper limitsurfaces freeing said mandrel means and said suspension means forremoval from said wellhead.

5. Pipe suspension apparatus comprising:

wellhead means having preformed annular grooves therein;

tubular mandrel means concentrically disposed in said wellhead means,said mandrel means provided with a reduced diameter cylindrical portionand a cylindrical portion of larger diameter than said reduced portion;

suspension means releasably held around said re duced diametercylindrical portion of said mandrel means by the side walls of saidwellhead means, said suspension means including segment means whoseouter face conforms to the shape of said preformed grooves within saidwellhead, said segment means resiliently biased away from said mandrelmeans, to engage said preformed grooves to free said suspension meansfor limited longitudinal movement relative to said mandrel means to aposition wherein said suspension means surrounds said larger diametercylindrical portion of said mandrel means which prevents disengagementof said segment means from said preformed grooves, and means adjacentsaid larger diameter portion abutting said segment means therebysuspending said tubular mandrel means within said wellhead means.

6. The combination of claim 5 and hold down means comprising a latchresiliently mounted on said mandrel means to laterally engage a portionof said suspension means in said position surrounding a larger diameterportion of said mandrel means preventing longitudinal movement of saidmandrel means in either direction relative to said suspension means.

7. The combination of claim 6 wherein said hold down means comprises alatch retractor mounted for longitudinal movement on said mandrel meansto laterally retract said latch freeing said mandrel means forlongitudinal movement in at least one direction.

8. Pipe suspension apparatus comprising:

wellhead means having preformed annular grooves therein, said grooveseach being defined by a bottom Wall and two side walls; tubular mandrelmeans concentrically disposed in said wellhead means, said mandrel meanshaving a plurality of downwardly facing shoulders thereon formed byuniformly reduced diameters thereon;

suspension means including segment means having outer facescorrelatively shaped to the form of said preformed grooves in saidwellhead, said segment means being releasably held to said mandrel meansby the sidewall of said Wellhead means and at least one of saiddownwardly facing shouldlers on said mandrel means, said suspensionmeans, wellhead means and mandrel means all being so constructed andarranged so that said segment means is resiliently biased to engage saidside walls of said preformed grooves on said wellhead as said. tubularmandrel means is lowered into said wellhead to release said segmentmeans from said mandrel means allowing said mandrel means to movedownwardly relative to said segment means to be stopped 'by at leastanother of said downwardly facing shoulders to lock said suspensionmeans to said Wellhead.

9. The combination of claim 8; and hold down means resiliently mountedon said mandrel means and engageable with said suspension means in saidlocked position to hold said suspension means in said locked positionwith said wellhead means, said hold down means being retractable torelease said suspension means for relative motion on said tubularmandrel means.

10. Pipe suspension apparatus comprising:

wellhead means having preformed grooves therein, said grooves each beingdefined by a bottom wall and two side walls, the lowermost surface ofthe lowermost said groove extending slightly into the bore diameter ofsaid wellhead means;

tubular mandrel means concentrically disposed in said 7 8 wellheadmeans, said mandrel means being conically gage said walls defining saidgrooves in said welltapered on the exterior thereof; head means.suspension means mounted on said mandrel means including segment means,the outer face of said seg- References Cited ment means conforming tothe shape of said pre- 5 UNITED STATES PATENTS formed grooves on saidwellhead, the inner face of said segment means being a tapered surfacecongasmussen 8212 forming to the shape of said tapered mandrel means,1902075 3/1933 Hreve 5 285 1 said segment means having a diameter largerthan 2690344 9/1954 fi X the diameter of the said lowermost surface ofsaid 10 3273915 9/1966 i X groove, said segment means having guide rodspass- 3345084 10/1967 i g X ing therethrough parallel to said taperedsurface, said guide rods having means thereon attaching said rods tosaid mandrel, said segment means being releasably CARL TOMLIN PumaryExaminer attached to said mandrel means by shear means 1 AROLA,Assistant EXaminel' whereby on downward motion of said mandrel meanssaid segment means engage said lowermost surface and said shear meansare sheared thereby freeing 1 129 136, 2 141 317 said segment means tomove radially outward to en-

